Perform OnRenderImage blit using an explicit temporary RT for the upscaled output. This can be blitted directly instead of needing an awkward command buffer, and it'll be less likely to cause issues than blitting from and to the same display buffer.

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/PostProcessLayer.cs

@@ -210,11 +210,12 @@ namespace UnityEngine.Rendering.PostProcessing
         CommandBuffer m_LegacyCmdBufferBeforeLighting;
         CommandBuffer m_LegacyCmdBufferOpaque;
         CommandBuffer m_LegacyCmdBuffer;
-        CommandBuffer m_BlitCmdBuffer;
         Camera m_Camera;
         PostProcessRenderContext m_CurrentContext;
         LogHistogram m_LogHistogram;
 
+        RenderTexture m_upscaledOutput;
+
         bool m_SettingsUpdateNeeded = true;
         bool m_IsRenderingInSceneView = false;
 
@@ -252,7 +253,6 @@ namespace UnityEngine.Rendering.PostProcessing
             m_LegacyCmdBufferBeforeLighting = new CommandBuffer { name = "Deferred Ambient Occlusion" };
             m_LegacyCmdBufferOpaque = new CommandBuffer { name = "Opaque Only Post-processing" };
             m_LegacyCmdBuffer = new CommandBuffer { name = "Post-processing" };
-            m_BlitCmdBuffer = new CommandBuffer { name = "Backbuffer blit" };
 
             m_Camera = GetComponent<Camera>();
 
@@ -286,10 +286,8 @@ namespace UnityEngine.Rendering.PostProcessing
             if (!finalBlitToCameraTarget && m_CurrentContext.IsSuperResolutionActive())
             {
                 // Blit the upscaled image to the backbuffer
-                m_BlitCmdBuffer.Blit(m_CurrentContext.destination, dst);
-                Graphics.ExecuteCommandBuffer(m_BlitCmdBuffer);
-
-                RenderTexture.active = dst;
+                Graphics.Blit(m_upscaledOutput, dst);
+                m_upscaledOutput.Release();
                 return;
             }
             
@@ -584,7 +582,6 @@ namespace UnityEngine.Rendering.PostProcessing
             m_LegacyCmdBufferBeforeLighting.Clear();
             m_LegacyCmdBufferOpaque.Clear();
             m_LegacyCmdBuffer.Clear();
-            m_BlitCmdBuffer.Clear();
 
             SetupContext(context);
             
@@ -716,9 +713,9 @@ namespace UnityEngine.Rendering.PostProcessing
 
             if (!finalBlitToCameraTarget && m_CurrentContext.IsSuperResolutionActive())
             {
-                // Use the main display buffer for temporarily storing the upscaled full-resolution image
-                context.flip = true;
-                context.destination = Display.main.colorBuffer;
+                var displaySize = superResolution.displaySize;
+                m_upscaledOutput = context.GetScreenSpaceTemporaryRT(widthOverride: displaySize.x, heightOverride: displaySize.y);
+                context.destination = m_upscaledOutput;
             }
 
 #if UNITY_2019_1_OR_NEWER